A Study on Some Special Forms of Holographic Ricci Dark Energy in Fractal Universe

Chattopadhyay, Surajit; Pasqua, Antonio; Roy, Sudipto

doi:10.1155/2013/251498

Cited by 10 publications

(10 citation statements)

References 33 publications

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“…In an expanding universe such as the one we have experienced, the scale factor increases monotonically as time passes, hence the redshift parameter has positive values which mean distant galaxies appear redshifted. On the other hand, (i) one can also extend our results by considering fractal description of the extended holographic energy [47], modified holographic Ricci dark energy [48], and new agegraphic dark energy [18], (ii) in Reference [49], the fractal ghost reconstruction of quintessence field was achieved. After comparing our manuscript with this paper, it can be seen that all of our results are agree with and extend those ones obtained in Reference [49].…”

Section: A Then´1supporting

confidence: 58%

Holographic Tachyon in Fractal Geometry

Saltı

Aydoğdu

2016

MCA

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The search of a logical quantum gravity theory is one of the noteworthy issues in modern theoretical physics. It is known that most of the quantum gravity theories describe our universe as a dimensional flow. From this point of view, one can investigate whether and how these attractive properties are related with the ultraviolet-divergence problem. These important points motivated us to discuss the reconstruction of a scalar field problem in the fractal theory which is a well-known quantum theory of gravity. Making use of time-like fractal model and considering the holographic description of galactic dark energy, we implement a correspondence between the tachyon model of galactic dark energy effect and holographic energy. Such a connection gives us an opportunity to redefine the fractal dynamics of selected scalar field representation by considering the time-evolution of holographic energy.

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Section: A Then´1supporting

confidence: 58%

Holographic Tachyon in Fractal Geometry

Saltı

Aydoğdu

2016

MCA

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“…In the theory T 1 with ordinary derivatives, the problem has been considered mainly with exotic dark-energy components, in flat 47,[57][58][59][60][61][62][63] as well as non-flat FLRW. 64,65 In these cases, late-time acceleration is possible, although the theoretical motivation is no more robust than in general relativity.…”

Section: About Cosmologymentioning

confidence: 99%

Multifractional theories: an unconventional review

Calcagni

2017

J. High Energ. Phys.

323

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We answer to 72 frequently asked questions about theories of multifractional spacetimes. Apart from reviewing and reorganizing what we already know about such theories, we discuss the physical meaning and consequences of the very recent flow-equation theorem on dimensional flow in quantum gravity, in particular its enormous impact on the multifractional paradigm. We will also get some new theoretical results about the construction of multifractional derivatives and the symmetries in the yet-unexplored theory $T_\gamma$, the resolution of ambiguities in the calculation of the spectral dimension, the relation between the theory $T_q$ with $q$-derivatives and the theory $T_\gamma$ with fractional derivatives, the interpretation of complex dimensions in quantum gravity, the frame choice at the quantum level, the physical interpretation of the propagator in $T_\gamma$ as an infinite superposition of quasiparticle modes, the relation between multifractional theories and quantum gravity, and the issue of renormalization, arguing that power-counting arguments do not capture the exotic properties of extreme UV regimes of multifractional geometry, where $T_\gamma$ may indeed be renormalizable. A careful discussion of experimental bounds and new constraints are also presented.Comment: 1+106 pages, 3 figures, 9 tables, 245 references. Review article (with several important novelties) through 72 questions; in some of them, there is text overlap with papers by the author, all indicated in the text. v2: references added, minor typos corrected, answers to questions 01, 59 and 68 expanded. v3: minor typos correcte

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“…While there are some studies about inflation [18,19] and gravitational-wave propagation [20,21] that constrain or propose possible effects in the cosmic microwave background and in gravitational-wave signals in multifractional spacetimes, the problem of dark energy has received less attention, except in the case with ordinary derivatives. The absence of cosmological vacuum solutions in the theory with ordinary derivatives [16] led some to explore scenarios with more or less exotic dark-energy components [22][23][24][25][26][27][28][29] (see also [30,31] for a thermodynamical approach). However, our point of view is that a sensible theory beyond Einstein should be able to describe cosmic acceleration without introducing dark-energy fields by hand.…”

Section: Introductionmentioning

confidence: 99%

Dark energy in multifractional spacetimes

Calcagni

Felice

2020

Phys. Rev. D

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We study the possibility to obtain cosmological late-time acceleration from a geometry changing with the scale, in particular, in the so-called multifractional theories with q-derivatives and with weighted derivatives. In the theory with q-derivatives, the luminosity distance is the same as in general relativity and, therefore, geometry cannot act as dark energy. In the theory with weighted derivatives, geometry alone is able to sustain a late-time acceleration phase without fine tuning, while being compatible with structureformation and big-bang nucleosynthesis bounds. This suggests to extend the theory, in a natural way, from just small-scale to also large-scale modifications of gravity. Surprisingly, the Hausdorff dimension of spacetime is constrained to be close to the topological dimension 4. After arguing that this finding might not be a numerical coincidence, we conclude that present-day acceleration could be regarded as the effect of a new restoration law for spacetime geometry.

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A Study on Some Special Forms of Holographic Ricci Dark Energy in Fractal Universe

Cited by 10 publications

References 33 publications

Holographic Tachyon in Fractal Geometry

Holographic Tachyon in Fractal Geometry

Multifractional theories: an unconventional review

Dark energy in multifractional spacetimes

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